Tissue bulking involves the implantation of bulking devices within tissue of a selected structure within a patient. By bulking the tissue of the structure, the bulking devices can alter the function of the structure. For example, bulking devices may be implanted proximate to the lower esophageal sphincter (LES) of a patient to treat gastroesophageal reflux disease (GERD). When implanted proximate to the LES, the bulking devices treat GERD by cooperating with the LES to increase the closing pressure of the LES, thereby reducing the likelihood of reflux flow of fluid from the stomach into the esophagus. As other examples, bulking devices may be implanted near the pyloric sphincter or within the fundus of the stomach to treat obesity, or proximate to a urethral or anal sphincter to treat incontinence.
Luminal walls, such as the esophageal wall, stomach wall, urethral wall and anal wall, include a plurality of layers. The layers of such luminal walls, from the inner lumen outward, include a mucosal layer, submucosal layer, and a muscular layer. Typically, bulking devices implanted within such luminal walls are implanted within the submucosal layer, or between the submucosal and muscular layers. For example, U.S. Pat. No. 6,401,718 discloses an esophageal bulking device for implantation in the submucosa in the vicinity of the LES. It has also been proposed to implant bulking devices within the muscular layer. For example, U.S. Pat. No. 6,595,909 discloses implantation of bulking devices within the muscular layer of the esophagus in the vicinity of the LES.
The submucosal layer comprises soft tissue. Consequently, bulking devices implanted within or directly beneath the submucosal layer may migrate from their intended position, and may even migrate into the mucosal layer. Devices that migrate into the mucosal layer may further migrate into the lumen and be lost, or may be lost as a result of natural sloughing of the mucosal tissue. Moreover, the pronounced protrusions into a lumen caused by bulking devices implanted within or near the submucosal layer can lead to undesirable erosion of the of the mucosal layer and contact between mucosal tissues disposed on opposite sides of the lumen. Even when implanted within the muscular layer of the luminal wall, the pronounced protrusions caused by bulking devices may lead to undesirable mucosal erosion and contact between mucosal tissues disposed on opposite sides of the lumen.
Table 1 below lists documents that disclose techniques for implantation of tissue bulking devices.
TABLE 1Patent NumberInventorsTitle2004/0037887Bourne et al.Bulking agent2004/0037865MillerObesity controlling method2004/0019388StarkebaumMethods and implants forretarding stomach emptyingto treat eating disorders2004/0009224MillerObesity controlling method2003/0199730Silverman et al.Method for treating tissuewith an implant2003/0188755MilbockerTreatment forgastroesophageal disease6,755,869GeitzIntragastric prosthesisfor treatment of morbidobesity6,725,866Johnson et al.Method for treatinggastroesophageal refluxdisease6,660,301Vogel et al.Injectable microspheresfor dermal augmentationand tissue bulking6,595,909Silverman et al.Method for treatingtissue with an implant6,591,838DurginImplant system andmethod for bulking tissue6,540,789Silverman et al.Method for treatingmorbid obesity6,401,718Johnson et al.Submucosal esophagealbulking device6,251,063Silverman et al.Method for treatingwall forminggastrointestinal tract6,238,335Silverman et al.Method for treatinggastroesophageal refluxdisease and apparatusfor use therewith6,098,629Johnson et al.Submucosal esophagealbulking device
All documents listed in Table 1 above are hereby incorporated by reference herein in their respective entireties. As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of the Preferred Embodiments and Claims set forth below, at least some of the devices and methods disclosed in the patents of Table 1 may be modified advantageously by following the teachings of the present invention.